1. Field of the Invention
The present invention generally relates to a power supply system and a power supply system operation method. More particularly, the present invention relates to a power supply system with a remote control circuit and to a power supply system operation method capable of simultaneously supplying a system with power through a power supply device and a battery.
2. Description of Related Art
The stability of the power source is very critical to the current electronic products. If an electronic product is supplied by unstable power, the stability and the reliability thereof would be affected. Therefore, in order to improve the power source stability, some electronic products are equipped with a power supply device and a battery to simultaneously provide the products with the required powers, as shown by FIG. 1.
FIG. 1 is a diagram of a conventional power supply system. Referring to FIG. 1, the conventional power supply system of FIG. 1 includes a conventional power supply device 101, a first switch 102, a charger 103, a second switch 104, a battery 105 and a system 106, wherein the output power of the conventional power supply device 101 is assumed 45 W. The conventional power supply device 101 supplies the system 106 with power through the first switch 102, meanwhile the conventional power supply device 101 charges the battery 105 through the first switch 102 and the charger 103 as well.
Since the prior art as shown by FIG. 1 is unable to keep the voltage of the conventional power supply device 101 the same as the voltage of the battery 105 by adjustment, thus, the conventional power supply device 101 and the battery 105 are not capable of simultaneously supplying the system 106 with power. When the load of the system 106 is increased to 50 W, the battery 105 is still unable to parallel supply the system with power; that is because the second switch 104 where the current I passes through uses a P-type metal-oxide-semiconductor transistor (PMOS transistor) containing a body diode and served as an isolation switch, so as to control supplying power to the battery 105 thereby. When the conventional power supply device 101 performs a protection action (for example, in the case where the load of the supplied system is beyond the rating output power of the conventional power supply device 101) or is not present, the second switch 104 would be on. Moreover, when the load of the system 106 is increased, the regular PMOS transistor containing a body diode fails to effectively rectify the current I, which results in burning the second switch 104 and further makes the battery 105 and the conventional power supply device 101 incapable of simultaneously supplying the system 106 with power.
In addition, since the prior art is unable to vary the output voltage of the conventional power supply device 101, the output voltage can not be adjusted within 9-13V to approximate the output voltage of the battery 105 and is accordingly unable to conform to the requirement of ‘Narrow Direct Current Voltage 2’ (also termed as ‘Narrow VDC 2’ or ‘NVDC2’) launched by Intel company. On the other hand, the conventional power supply device 101 is required to provide at least the electric power of the load of the system 106, but it fails to achieve the goal by using other power source to provide a parallel power supply, therefore, the prior art can not flexibly design the volume of the conventional power supply device 101.